Integrated dielectrophoretic and impedimetric sensor for microbial detection

Overview

This solution is an integrated biosensing platform that combines dielectrophoretic (DEP) concentration with electrical impedance measurement to detect and quantify microbial cells, including bacteria, yeast, and mold. By selectively concentrating target microbes on interdigitated T-electrodes using frequency-tuned DEP forces, the system amplifies the capacitance and dielectric changes between electrodes. The resulting impedance signal enables highly sensitive quantification of microbial load without the need for labels, amplification steps, or highly trained operators.

The technology addresses a critical need in clinical diagnostics, food safety, environmental monitoring, and bioprocess quality control, where rapid, sensitive, and easy-to-use microbial detection remains a challenge. The underlying concept has already been validated for protein and miRNA biomarkers, achieving sub-femtomolar limits of detection in under 10 minutes. The research group has received a US patent for the invention and an NSF CAREER award to advance the platform toward point-of-care screening for cancer, obesity, and addiction-related biomarkers, demonstrating strong institutional and federal support.

Technical specifications

Core mechanism:

• Dielectrophoretic concentration: An applied alternating electric field exerts frequency-dependent DEP forces on microbial cells, pulling them toward the electrode surface where the field gradient is highest. The optimal frequency is tuned to the dielectric properties of each target microbe.
• Impedimetric readout: Once microbes are concentrated near the interdigitated T-electrodes, changes in capacitance and dielectric properties of the medium are measured as impedance shifts. A regression-based algorithm converts impedance values into microbial concentration.

Key features:

• Label-free and amplification-free workflow reduces assay cost and complexity
• Detection completed in under 10 minutes with minimal user training required
• Patented interdigitated T-electrode design compatible with commercial impedance analyzers
• Frequency-tunable selectivity enables targeting of different microbial species
• Adaptable platform with prior validation for miRNA and protein biomarkers at sub-femtomolar sensitivity

Target applications:

• Clinical point-of-care screening
• Food and beverage safety testing
• Environmental water and soil monitoring
• Biopharmaceutical and fermentation quality control

Technology readiness level

The core impedance-based biosensing concept has been experimentally validated for protein and miRNA detection, achieving limits of detection below 1 fM and assay times under 10 minutes. The technology is protected by a recently issued US patent, and ongoing work is supported by a five-year NSF CAREER award of $500K. The microbial-specific extension is at an early-to-mid stage of development, with three defined aims: characterizing DEP behavior of cultured bacteria, yeast, and mold on the patented electrode platform; building impedance-based quantification algorithms; and automating the workflow for point-of-care and real-world validation. The platform is well positioned for collaborative development, licensing, and sponsored research partnerships to accelerate translation into commercial diagnostic products.